feat: add best_blockchain in /status payload

[alexruzenhack]

Motivation

Expose the best_blockchain through an interface.

Acceptance Criteria

• Must return the peer_best_blockchain property in the connected_peer body when /status is requested
• Must return the best_blockchain property in the dag when /status is requested
• Make some adjustments in the test and fix some issues from the previews get_best_blockchain PR

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

Closes:

• Add best_blockchain for each connected peer in the /status payload #680
• Add best_blockchain for my_peer in the /status payload #681
• Update /status payload in API documentation #682
• Test GET /status #683

[codecov]

Codecov Report

Merging #704 (17cdfe4) into master (97f2471) will increase coverage by 0.08%.
The diff coverage is 78.57%.

@@            Coverage Diff             @@
##           master     #704      +/-   ##
==========================================
+ Coverage   84.52%   84.61%   +0.08%     
==========================================
  Files         253      252       -1     
  Lines       21708    21717       +9     
  Branches     2941     2941              
==========================================
+ Hits        18349    18376      +27     
+ Misses       2718     2705      -13     
+ Partials      641      636       -5     

Files Changed	Coverage Δ
hathor/p2p/utils.py	73.87% <66.66%> (-1.40%)	⬇️
hathor/p2p/resources/status.py	100.00% <100.00%> (ø)
hathor/p2p/states/ready.py	93.89% <100.00%> (-0.05%)	⬇️

... and 3 files with indirect coverage changes

The base branch was changed.